March 04, 2014
1 min read

Smoking increased risk for ER-positive breast cancer

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Women who are current or recent smokers are at increased risk for breast cancer, especially ER-positive breast cancer, according to results of a population-based study.

Christopher Li, MD, PhD, of the Fred Hutchinson Cancer Research Center in Seattle, and colleagues evaluated data from women aged 20 to 44 years who were diagnosed with breast cancer between 2004 and 2010.

Of the women, 778 had ER-positive breast cancer, and 182 women had ER- and PR-negative and triple-negative breast cancer. Researchers included 938 women without breast cancer in the control population.

Overall, smoking was associated with a 1.3-fold (95% CI, 1.1-1.7) increased risk for breast cancer.

Li and colleagues also analyzed breast cancer risk according to disease subtype. They found smoking further increased the risk for ER-positive breast cancer (OR=1.4; 95% CI, 1.1-1.8), but not triple-negative breast cancer (OR=1.1; 95% CI, 0.7-1.6).

Women with a ≥10 pack-year history had a 1.6-fold (95% CI, 1.1-2.4) increased risk for ER-positive breast cancer compared with controls. However, longer pack-year smoking history did not increase the risk for triple-negative breast cancer (OR=1; 95% CI, 0.5-1.9).

“The health hazards associated with smoking are numerous and well known,” Li said in a press release. “This study adds to our knowledge in suggesting that with respect to breast cancer, smoking may increase the risk of the most common molecular subtype of breast cancer but not influence risk of one of the rarer, more aggressive subtypes.”

Disclosure: See the study for a full list of the researchers’ relevant financial disclosures.